Improving the Pass-Through Hinge
hen works of art on paper their frames in museums and other
are secured with Japanese public collections, the pass-through
tissue and paste hinges, the hinge presents a problem in that the
hinges must be applied by skilled per- hinge is exposed on the back of the
sonnel who are versed in appropriate back mat and can be disturbed as the
application and drying techniques. mat is moved about. If the work is per-
Even well-applied hinges may manently stored in a frame, however,
not operate successfully if passing the image through has benefits.
they are secured too tightly It reduces the time needed for dry-
to the back mat. A hinge ing since the hinge can be secured to
firmly pasted to the back the back of the back mat with gummed
mat will fix the art to the tape in place of the usual paste attach-
board at that point and, ment to the front side of the back mat.
during changes in relative The passage of the hinge through the
humidity, the paper may slit in the back mat also allows a mod-
expand more rapidly and icum of lateral movement for the hinge
extensively than the board can. along the length of the slit. This can be
Customers who expect that their useful in addressing the problem of
work should remain perfectly flat will overly intimate bonding between the
obviously be upset if it cockles at its art and the back mat.
edges between the hinges. In addition, The design of the slit is critical. To
they may not be satisfied with an ensure that the hinge is not locked up
explanation of the risk to the value of by friction with the fibers of the board
their work which overall mounting as it passes through, it has been recom-
poses. Thus, it is important to engineer mended that the slits be cut with a
the attachment of the hinge to the back bevel, not perpendicular to the plane of
mat so that the art is supported gently the board. The beveled cut also makes
and steadily without too intimate a insertion of the hinge through the
bond. board much easier.
One method of attachment which When the beveled slit is made it
is used more frequently in shops than it should be cut so that its top side will be
is in institutions is the pass-through just behind the edge of the art and it
hinge. Since works are stored outside will angle out and back, away from the
70 PFM i April 1998
edge of the art. The hinges should have been situated so passed through with paper sleeves, as before, and secured
that their adhesion to the art ends just shy of the outer with gummed paper or linen tape (figure 1).
edge of the art. Thus, when the hinge is passed through, This more elaborate pass-through slit diminishes the
the slit will be under the edge of the art and will not be mass of the board at the point at which the hinge transits
able to engage the art’s edge if there is any warpage. Direct- and creates a more physically sympathetic setting. It is
ing the cuts out from the edges of the art, rather than in important to make the cuts carefully so that they do not
behind them, means that the hinges operate as if they were create an unsightly opening in the front of the back mat
pendant hinges rather than folded hinges and reduces the which might show under the edge of translucent papers.
effects of friction. All of these issues, plus the use of folded This is yet another advantage to this method. If a
paper insertion sleeves, have been explored previously work were to be removed from a back mat through
(PFM Preservation Supplement, February 1994). which hinges had been passed using prior techniques, the
As well as such techniques may work, they can be unthreading of the hinges from the slits could be difficult
improved. Central to the successful practice of preserva- and hazardous to the hinges and, ultimately, to the edges
tion framing is the commitment to the improvement and of the art. “Teasing” the hinges back through the slits
refinement of its materials and techniques. Changes are often results in torn or dislodged hinges. The bending of
never made for their own sake, but rather in response to the back mat required to open the slits is also potentially
weaknesses in current methods. If these ordinary slits are dangerous to the art. The inverted V-shaped slit lends
used to pass through light weight hinges on a delicate itself to easy rethreading of hinges back through the back
sheet of paper, it is easy to see that they still offer too mat and enhances safe removal of the art.
much friction and too strong a hold for such fragile Next month we will look at an improvement for
material. This is not a minor issue, since the pass- cross pieces used with folded hinges to further this
through hinge is most useful with light weight papers inquiry into the possibilities for gentle, steady support of
since they are often translucent. The attachment of the works which must be housed and displayed so that their
hinge to the front of the back mat would therefore show edges are exposed. s
through the art.
What is called for is a redesign of the slit which reduces
the mass of the board where the hinge passes through and
allows for the more gentle operation of the hinge.
One method of achieving this employs two slits cut
into the back mat at the same place but with opposing
bevel angles. This is essentially an inverted V-groove. The
slit should be situated exactly as before (just beneath the
edge of the art). The slits can now be cut with a cutter or
by hand using a straightedge, depending on the skill of
the craftsperson. There will be a V-shaped strip of board
which will be partially released from the back of the back
mat by the cutting. This strip can be trimmed out as its
ends and the slit will be complete. The hinges can be
72 PFM i April 1998